Typically, a damascene process is used to form interconnects for semiconductor processing. First, a trench is formed in a substrate. A barrier metal is deposited to prevent the metal which will form the interconnect from diffusing through the substrate. Typically, copper or aluminum is then deposited until the copper fills the trench, forming an interconnect.
As the copper fills the trench, there is a finite probability of the copper pinching off, leaving a void within the copper interconnect. Because copper is subject to electromigration, any void can work as a nucleus for growing larger voids within the interconnect. A void can, therefore, grow to fill a portion of the copper interconnect. When this occurs, the copper interconnect fails.
Accordingly, what is needed is a system and method for reducing the impact of voids and electromigration in such interconnects. The present invention addresses such a need.